Hydrodynamic machine



Jan. 16, 1951 Filed May 25, 1944 W. FERRIS HYDRODYNAMIC MACHINE 6 Sheets-Sheet 1 INVENTOR WALTER F E RRIS Jan, 16, 1951 w. FERRIS 2,538,194

HYDRODYNAMIC MACHINE Filed May 25, 1944 6 Sh eets-Sheet 2 INVENTOR WALTER FERRIS wf w Jan. 16, 1951 w. FERRIS 2,538,194

HYDRODYNAMIC MACHINE Filed May 25, 1944 6 Sheets-Sheet 3 9 I ;F|e.4 lo

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NVENTOR WALTER [FERRIS BY .1

Jan. 16, 1951 w. FERRIS HYDRODYNAMIC MACHINE 6 Sheets-Sheet 4 Filed May 25, 1944 FIG. 7

5 ZAN 6 m 5 llnflllll 1 llrlllllllllw I] J u n A I INVENTOR WALTER FERRIS BY 1951 w. FERRIS HYDRODYNAMIC MACHINE 6 Sheets-Sheet 6 Filed May 25, 1944 n rm. h

INVENTOR WALTER FE-RRIS V. I 3 TWM w (Ill/Ill Patented Jan. 16, 1951 HY-D RD'DEENAMIC .MAGHINTE Walter Ferris, Milwaukee, Wis, ass'ignor to The O'ilgear Company, Milwaukee, Wis., a corporation of Wisconsin Application MayI25, 1944, Serial No. 537,346

This invention relates to hydrodynamic machines of the type havin :a plurality of .va-nes slidably fitted in slots formed substantially radially in a rotor, .a spacer ring arranged around the rotor and spaced therefrom, cheek plates arranged upon opposite ends of the rotor and held in spaced relation by the spacer ring, and a vane track arranged around the rotor inside of the spacer ring and including a plurality of bridges which cooperate with the vanes to divide the space between the rotor and the spacer ring into high pressure and low pressure .chambers.

Such :a machine ordinarily has two diametrically opposed sealing bridges which :are arranged close to the rotor and two working bridges which are spaced 90 from the sealing -bridges and are spaced from the rotor when the machine is performin useful work at which time the outer ends of the vanes ride along the vane track and pass through the low pressure and high pressure chambers successively. If the rotor is rotated, the vanes passing across the working bridges will transfer liquid from the low pressure chambers to the high pressure chambers and the machine will function as a pump. If motive liquid is supplied to the .high pressure chambers, it will act upon the outer end portions of the vanes in contact with the working bridges and rotate the rotor, thereby causing the machine to function .as a motor. 'If the Workingbridges are moved toward or .from the rotor, the displacement of the machine will be varied and, if the outer bridges are moved inward close to the rotor and the-inner bridges are moved outward, the machine will be reversed to thereby reverse the direction of flow if the machine is functioning as a pump or to reverse the direction of rotation if the machine is functioning as a motor.

In prior machines of this type, the high pressure and low pressure chambers communicate with an external circuit through ports which extend axially from the chambers but the liquid pumped by or required to operate a machine of large volumertic capacity cannot flow through axial ports without excessive head losses as will presently be explained.

The outer ends of vanes passing through the high pressure chambers are subjected to the pressure therein. In order to prevent this pressure from moving those vanes inward out of engagement with the vane track, one of the cheek plates is provided in its inner face with vane slot ports which "are spaced radially inward "2 from the high pressure and low pressure chambers .and with which the inner ends of the vane slots register successively .as the rotor rotates,

and the vane slots that are radially inward from the high pressure chambers are supplied with liquid vat a pressure :at .-least as high as the pressure in the high pressure chambers.

In prior machines, the vane slot ports that are radially inward from the high pressure chambers communicate through holes in the cheek plate with grooves which are formed in the outer face of the cheek plate and are :connected to a source of high pressure .liquid. The outer .face of the cheek plate is in contact with afiat surface which :closes the open sides of the grooves .but the pressure causes liquid to seep from the grooves and form .-a film between the cheek plate and the flat surface. The pressure extends into this film so that the liquid in the groove and in the film exerts sufiicient (force upon the cheek plate to deflect it against the :end of the rotor and cause it to impose a drag or brake load thereon.

The ,present invention has an object to provide a hydrodynamicmachinepf the sliding vane type which is free from the objectionable characteristics mentioned above.

Another object is to provide a vane type hydrodynamic machine with hydraulic means for adjusting the bridges thereof and means .-f.or supplying liquid to said hydraulic means first at .a low pressure and automatically increasing the pressure in response to the pressure in said machine exceeding a given value.

Another object is to providea vane type hydrodynamic machine with a vane track having -a bridge which constitutes the piston of .a servo motor for adjusting that bridge.

Another object is to provide means to ,positively limit the movement of .a vane track bridge.

Another object is to provide .a vane type hydrodynamic machine that may be made to have .a large volumetric capacity.

Another object is to provide a vane type'hydrodynamic machine with radial ports so that it A may have a large volumetric capacity.

Another object is to provide a vane typehydrodynamic machine withnovel means for effecting reversal thereof.

Another object is to provide .a check plate that will not be deflected by the liquid supplied to the vane slot ports therein.

Another object is to provide a hydrodynamic machine with means "forsupplying 'liquidat alow pressure to "the vane slot ports "to initially urge a machine in which the invention is embodied,

the View being taken on the line |I of Fig. 2 and the lower part of the casing being broken away in order to show the working parts on a larger scale.

Fig. 2 is a transverse section taken across the end of the rotor as indicated by the line 2-2 of Fig. 1.

Fig. 3 is an enlarged perspective view of one of the vane track sections shown in Fig. 2.

Fig. 4 is a View taken in the plane of the line 44 of Fig. 2 but drawn to a larger scale and showing the means for connecting the vane track sections to the bridges and the means for moving th bridges radially outward.

Fig. 5 is a view drawn to the same scale as Fig. 4 and illustrating the mechanism for moving a bridge toward the rotor and for controlling the movement of the bridge away from the rotor, the view being taken on the longitudinal centerline of the machine in the same plane as Fig. 1 and as indicated by the line 5-5 of Fig. 6 but it shows the bridge in a position different from that shown in Figs. 1 and 4.

Fig. 6 is a fragmentary section taken on the line 6-6 of Fig. 2 and showing the arrangement of the springs for urging a bridge radially outward, the view being drawn to the same scale as Fig. 5.

Fig. 7 is a view taken approximately on the irregular line 1-1 of Fig. 8 and showing the radial ports through which liquid flows to and from the rotor.

Fig. 8 is a transverse section taken on the line 8-8 of Fig. 1 and illustrating the passages through which liquid flows to and from the ports shown in Fig. 7.

Fig. 9 is a diagrammatic view illustrating the hydraulic circuits of the machine.

- The machine shown in the drawings is intended to function as a pump and it will be described as such but the machine will function as a motor if it is supplied with motive liquid, and it is to be understood that the present invention is in no way limited to a pump.

Asshown, the pump has its mechanism arranged within a casing I having formed therein a cylindrical recess 2 which is larger in diameter at its front than at its rear to receive an end head 3 which closes recess 2 and has a peripheral flange 4 formed thereon and extending around the inner periphery of the enlarged part of recess 2. Flange 4 has the same inner diameter as the rear part of recess 2, and an upper portion of. flange 4 is cut away to accommodate a control mechanism as will presently be explained.

Recess 2 contains a spacer ring 5 which is fitted in the rear part thereof and within the rear part of flange d. A rotor 6 is arranged inside of spacer ring 5 and provided with a plurality of substantially radial vane slots 1 each of which has a vane 8 slidably fitted therein.

When the machine is performing useful work, each vane moves outward and draws liquid into its slot during one part of a revolution of the rotor and it moves inward and expels liquid from its slot during the succeeding part of a revolution of the rotor. The vane slots cannot be extended radially inward but very little beyond the innermost positions of the vanes without dangerously weakening the rotor. Consequently, if each vane slot had the same width throughout its length, the flow of liquid to the inner end of a vane would be greatly restricted when the vane was in its innermost position. In the present instance, the rotor is considerably longer than the rotors of the prior machines and, in order to provide unrestricted flow of liquid to the inner end of each vane throughout the entire length thereof, the inner end of each vane slot 7 is enlarged in the form of a circular bore as shown in Figs. 2 and 7.

Spacer ring 5 and rotor 6 are arranged between a check plate 9, which is fitted in the rear part of recess 2 and engages the rear wall. thereof, and a cheek plate I 0 which is fitted within flange 4 and engages a gear pump cover plate H which is also arranged within flange 4 and engages the inner face of end head 3. The cheek plates, spacer ring, gear pump cover plate and end head are rigidly clamped together by a plurality of bolts I2 which extend therethrough and are threaded into the rear part of casing l, spacer ring 5 being just enough longer than rotor 6 to provide running clearances between the ends of the rotor and the adjacent faces of the cheek plates. 7

Rotor 6 is splined upon and driven by a drive shaft 16 which extends through cheek plates" 9 and I6 and through cover plate I! and is journaled in suitable bearings carried by easing 5 and end head 3 respectively. Drive shaft l6 also drives a gear pump having one gear ll splined upon shaft [6 and its other gear l8 meshing with gear lfland journaled upon a stub shaft H) which is fixed in end head 3. Gears i1 and i8 are arranged in a suitable pumping chamber 26 which is formed inend head 3 and has its open side closed by cover plate ll. Pumping chamber20 communicates with an external circuit through passages which do not appear in shown schematically in Fig.9. 1 v

The outer. ends of vanes 8 engage a smooth track surface formed upon the inner periphery of an endless vane track of the type described and claimed in application Serial No. 530,425 filed April 10th, 1944 by Walter Ferris. ,The Vane track consists primarily of four identical bridges 24, '24, 24 and 24, which are equally spaced around rotor 6 as shown in Fig. 2, and four identical track sections 25, 25 25 and 25 which are arranged between adjacent bridges and pivotally connected thereto. The tracksections are extensible and the bridges are adjustable toward and from the rotor to vary the displacement of the pump, the track surface on each tracksection is concave, the track surface on each. bridge is concave intermediate its ends for a distance at least as great as the angular disstance between the outer ends of two adjacent Fig. 1 but are vanes and it is convex adjacent each of its ends 28 and 29 arranged upon-opposite esides'thereof and each segment is preferably fixed to one 'of the parts as by means of a pin 30. Each track section has a concave track surface formed upon its inner face and,':.as explained in application Serial No. 530,425, segments 28 .and 2.9 are telesoopically connected to parts .26 and 21 in such a manner that they :hold "the track surfaces thereon in circumferential alinement with each other while permitting parts 25. and 21 to move toward and from each other to vary the :length of the vane track, the adjacent ends of parts 26 and 21 being complementary :to each other and extending diagonally inward from opposite sides to provide an unbroken path for the vanes in all positions of parts 26and121.

In order to provide the smoothest possible radial movements of the vanes, the *track sections should be pivotally connected torzadjacent bridges at points spaced as far radially outward as may be .conveniently possible within the available space. To this end, each track section part 26 has two posts .3! and 32 rigidly secured thereto, each track section :part 21 has two posts '33 and 3d rig-idly secured thereto, and the outer ends of the posts are provided with suitable holes so that the posts may be pivotally connected to the bridges as will presently be explained.

Bridges 24, 2M, 24 and 24 are arranged, respectively, in recesses 35, 35 35 and "35 which are formed in spacer ring as shown in Fig. .2. Each bridge is closely fitted between the sides of its recess and between check plates Sand 'l'll, so that the bridges and the vanes in contact themwith divide the space between the periphery of rotor t and the inner periphery of spacer ring 5 into alternate intake and discharge "chambers. In prior pumps of this character, the intake and discharge chambers are connected to opposite sides of an external circuit through ports which extend axially therefrom through oneof the check plates. This arrangement is entirely satisfactory in pumps of the sizes ordinarily used but it .is not 'at all satisfactory in large pumps for the reason that an increase in capacity does not result in 'a proportional increase in the area of axial ports.

The volumetric capacity of a vane pump is determined by the peripheral speed of its rotor, the diameter of its rotor, the length or thickness of its rotor and its stroke or the distance that the vanes extend beyond the periphery of the rotor. Since pumps are ordinarily run at the highest practical rotary speed and since increasing the diameter would increase the rubbing speed (that is, the speed at which the ends .of the vanes slide along the vane track), increasing either the rotary speed or increasing the diameter of the rotor beyond the diameter necessary to provide sufficient metal between the shaft bore and the vane slots is not a practical way to provide large increases in volumetric capacity. Even if the diameter of the rotor could be readily increased, an increase in rotor diameter would result in only a proportionalincrease in displacement but the weight of the pump would increase in accordance with the square of the diameter.

if the stroke of the pump should be increased enough to cause the pump to have a large displacement, the vanes in contact with the pumping bridges would extend so far from'the periphery of the rotor that vanes of proper thickness would be bent or broken by the high pressure created by the pump, the thickness of the vanes 6. being slimited @due to the fact that, when a vane is massing :across a pumping bridge, :hig-h pressure acts upon the :full area of the inner end of the vane shut acts upon only about one half of the area .of the outer end of the vane so that the pressure acting upon the differential zarea forces the vane against the bridge and, if the vane should be too thick, it 'would be urged against the bridge with such .force that excessive wear :of the bridge and vane would result and the emciency of :the pump would be reduced. Gonsequently, increasing the stroke to obtain .a large displacement :is impractical.

Increasing the length of the rotor :causes .a proportional increase ii-nthe displacement of the pump ibut the space between the periphery of the rotor-:and the wane track remains unchanged so "that the :area of axial ports cannot be increased lbut the flow through the port :must increase in proportion to the increase in .displacement. C'onsequen'tly, liquid cannot flow through :an :axial port to and irom the space between the rotor and the vane track of .a large capacity pump without excessive head losses. In

fact, a large apump could not draw liquid from :an

adjacent reservoir "through an axial port fast enough to keep the .space between its rotor and vane track completely filled 'vdth liquid.

The pump illustrated in the drawingsis adapted to be made in large sizes, that is, it is capable of having a large volumetric capacity. In order to avoid the head losses incident to axial ports, each :of track sections 25, 25 .and 255 :is provided with a radial port or opening 40 as shown in Fig. :3. 'The ports 40 in track sections 25, 25 25 and 215 communicate, respectively,

. with four parts ill, Al tl- .and 41 "which, as

shown in Figs. :2 :and 7, .are formed in spacer ring 5 and incheek .plate 9. As shown in Figs. '7 and 8, ports 41 and 41 communicate, respectively, through two passages 42 :and 4 2-with an annular passage #5 which is formed in casing 1 around the hub of shaft t6 and has two branches in :and 48.. Ports Al and M commun-icate, respectively, through two passages 42 and 42 with an :arcuate passage 43 which is spaced radially outward from passage 46 and has two branches 44 and 45. Branch passages 44 ands? connect the pump to an 'externalycircuit and branch passages 45 and 48 connect the pump to an automatic suction "valve as will presently be explained.

As previously explained, each vane track section is pivota'lly connected to adjacent bridges by means of the posts .3l,, 3-2, 33 and 34 shown in Fig. The two posts fixed to each track section part 26 or 25! extend into two recesses four of which are :formed in each bridge, and both of these posts are journa'led :upon a pivot pin or shaft which extends through the bridge and the cheek plates. For example and as shown in Fig. 4 the posts 31 and 32 which are fixed to part 26 of track .section 25 extend, respectively, into two recesses 5| and 52 which are formed in bridge 24., and both of posts 3! and 32 are journaled upon a long pivot pin 53 which extends through the bridge and has its opposite ends arranged in two recesses 54 and 55 which are :formed in cheek platesil and 10 respectively. .One end of track section 25 is similarly connected to the other side of bridge 24 and the other ends of track sections 25 and 25 and both ends of track sec-- tions 25 and 25* are similarly connected to the other bridges.

Pivot .pin 53 extends through two bushings 56 7. and 51 which are fixed in bridge 24 and extend from opposite sides thereof into recesses 54 and 55 to provide stops to engage the inner walls of recesses 54 and 55 and positively limit the inward movement of the bridge and thereby prevent the vane track from being urged against the periphery of the rotor by the displacement varying mechanism to be presently described.

Pin 53 provides an anchor for two springs 58 and 59 arranged, respectively, in two recesses 69 and 9f which are formed in cheek plates 9 and II],

respectively, and extend radially inward from the peripheries thereof into communication with recesses 54 and 55 respectively. Springs 58 and 59 have their inner ends attached to pin 53 and their outer ends attached, respectively, to two pins 62 and 63 which are arranged within suit-" able slots formed in the cheek plates and extending across recesses 60 and 6| respectively. Pins 62 and 63 bear against the inner ends of their slots and enable springs 58 and 59 to urge bridge 24 outward. The other end of track section 25 and both ends of the other track sections are similarly connected to the adjacent bridges so that the inward movement of each bridge is limited by stops 56 and 51 and, as shown in Fig. 6, each bridge is urged outward by two springs 53 and two springs 59.

As previously explained, bridges 24, 24 24 and 24 are closely fitted, respectively in recesses 35, 35 35 and 35 and between cheek plates 9 and It. The arrangement is such that motive liquid may be directed to and from the outer ends of the recesses to enable each bridge to function as the piston and its recess to function as the cylinder of a servo-motor for moving that bridge toward the rotor. The flow of liquid to and from recesses 35, 35 ,.35 and 35 is controlled, respectively, by four follow-up valves 51, 61 61 and 61.

Since the flow control means for all four bridges are identical, a description of one will suflice for all. For example and as shown in Fig. 5, bridge 24 is controlled by a valve 61 which is fitted in a bore 68 formed in bridge 24 and in spacer ring 5. Valve 61 controls communication between a supply passage 69 and a passage 59 and between passage 19 and a discharge pas-i sage H all of which are formed in bridge 24.

Passage it connects the outer end of recess 35't'o bore 68 at a point intermediate the ends thereof.

Passage 69 communicates with bore 68 at a point: spaced radially inward from passage 10 and it is constantly supplied with motive liquid'as will presently be explained. Passage H communicates with bore 58 at a point spaced radially outward from passage 10 and it connects bore 68 to a passage I2 extending through cheek plate 9 into communication with an annular passage 13 which is formed in the periphery of cheek plate 9 and in the rear face of cheek plate 9 adjacent to periphery thereof.

Passage 13 is connected to'drain through a passage 14 having a check valve 15 arranged therein. Likewise and as shown in'Fig. 1, gear pump cover plate H has an armular passage 16 formed in its periphery and connected todrain through a passage 1! having a check valve 18 arranged therein. Check valves 15 and 18 offer a low resistance, such as 10 lbs. per sq. in, to the discharge of liquid therethroiigh tothereby keep casing l filled with liquid and to provide lubrication for the bearings.

Valve (Fig. 5) has formed therein a cannelure which is exactlythe same length as the distance between the adjacent edges of passages 8 69'and H and so located that valve 6'! normally blocks communication between passages 69, I0 and I I.

Valve 61 is adapted to be moved inward mechanically, as will presently be explained and, when it moves inward, it opens passage 69 to permit liquid to flow therefrom through bore 68 and passage 19 to the outer end of cylinder 35 and move bridge 24 inward, and bridge 24 in moving inward will tend to close passage 69 as fast as valve 61 opens it so that movement, of bridge 24 ceases substantially as soon as movement of valve 61 ceases.

-Valve 61 is urged outward by a spring 19 arranged in the inner end of bore 68 and in a recess formed in the inner end of valve 61. When valve 61 is permitted to move outward, it opens passage H and then the forces exerted upon bridge 24 by the pressures in the pump and by springs 58 and 59 will move bridge 24 outward and cause it to expel liquid from the outer end of recess 35 through passage 10, bore 68 and passages H, 12, I3 and 14 to drain. Bridge 24 in moving outward will tend to close passage H as fast as valve 61 opens it so that movement of bridge 24 ceases substantially as soon as movement of valve 61 ceases.

When valve 6'! is stationary, bridge 24 is held stationary for the reason that liquid cannot flow into recess 35 to move bridge 24 inward and the liquid trapped in recess 35 prevents bridge 24 from being moved outward by the forces exerted thereon. If bridge 24 should move in one direction or the other from an adjusted position, it would-open passage 69 or passage H just as soon as it started to move and opening one or the other of those passages would cause bridge 24 to be returned to its adjusted position before it had moved an appreciable distance therefrom.

valves 61, 67*, 61 and 61 are urged outward by their springs 19 into engagement with a cam ring 80 which is arranged around spacer ring 5 and rotatably supported within the enlarged part of recess 2 by an annular roller bearing 8| as shown in Figs. 1 and 2, axial movement of cam ring- 80 being prevented by flange 4 and the shoulder formed by' enlarging the front part of recess 2.

The inner periphery of cam ring 80 constitutes a .cam track which is concentric with rotor 6 except at four places where it is recessed to form four cam surfaces 82, 82 82 and 82 for effecting operation of valves 61, 61 61 and 61 respectively. The parts are so proportioned that a valve-in engagement with a concentric portion of the cam track on cam ring 80 will be held in its innermost position and a valve in engagement with one of the cam surfaces will have been moved outward from its innermost position a distance proportional to the distance the end of the valve moved along the cam surface from the adjacent concentric portion of the cam track.

Since each bridge moves with its valve and occupies the same relative position as its valve aspreviously explained, a bridge will bev in its When cam ring is in its neutral position, all

four valves are. in engagement with concentric portions of the camtrack so that all: four bridges are in their innermost positions and pump dis.- placement iszero.

When cam. ring 80 is rotated; from its neutral osition clockwise in respect toFig...2,.valves li'l' and 61 will ride. along the. concentric portions of the cam track so that'bridges 2.4 and 24;! are held in their innermost positions; but valves E1 and 61* will ride, respectively, ontocamsurfaces 82 and 82 which will permitvalves- 6!- and. 61 to move outward and cause bridges 24 and Z4 to move outward.

Holding bridges 24 and 24 close to the rotor and. moving bridges 24 and 24* away from the rotor, causes the pump to discharge liquid one direction at. a rate. dependent, upon thev distances that bridges 24. and 241 are moved from. their innermost or zero displacementpositions. For ex ample, if rotor 6 is rotated inthedirectionof the arrow, the vanes. passing. across. bridge 24 will transfer liquid from: port, 4] toports 41 and the vanes passing across' bridge M will transfer liquid from. port 4 l to ipQEt M so. that the. pump draws liquid through ports 4t andv 41 and dis chargesiit through ports 4 l and. 4I. If cam ring 80 is rotated far. enough to permit valves 61 and 51 to move outward until they have caused bridges 24' and 2 tostall against the. outer ends of recesses 35 and 35 as shown in Fig. 2-, pump displacement will be maximum and the pump will deliver liquid at its maximum rate through ports ll and M9.

When. cam ring 80 is rotated counterlo'ckwise from the position shown. in' Fig. 2;, cam surfaces 82 and 82 will force valves 61 and 61 inward which will cause bridges 24 and 24 tomove in.- ward and reduce pump displacement until cam ring 80 reaches its neutral position at which time bridges 24 and 2-4 -will have been moved to their innermost positions and pump displacement will be zero.

Continued rotation of cam ring 80 will bring cam surfaces 82 and 82 into alinement" with valves lil and 61 which will then move outward and cause bridges M and 2 4 to move outward but valves 51- and' 61 will remain in contact with concentric portions of the cam: track so that bridges 2-4 and 24*" are held in their innermost positions. With bridges 24 and 24: in their innermost positions and bridges 2 4 and 2 1 moved outward, the pump will function as previously explained but it will deliver liquid in the opposite direction at a rate dependent-upon the distances bridges 2A and 24 are moved from their innermost positions.

Cam ring 80 is rotated through a pin 133 (Figs. I and 2) which. connects it to a link 84: and to the connecting. rod 85 of a piston. 8fi= fitted in a cyl inder 8.! which is: formed in or connected to casing and to which motive liquid is: constantly supplied through a channel? 88 from. a suitable source. For example, channel 8 maybe connected to gear pump li -i8 as shown; in 9:

Link 84 connects pin- 83' to one end. of a-lever 98 the other end of which is" pivotally connected to casing l by a shaft 93ft. Lever: 90 providied intermediate its: ends with a. roller 92': to en'- gage the inner end of a sleeve 93 having a piston 94 arranged thereon and closely fittedin a cylinder 95'.

Piston all and cylinder 95' constitute a servomotor which is controlled by a rotary valve 96 journaled in sleeve 93 and in the head of cylinder 95 and provided on its outer end means, such as alever- 31 for rotating it. Bi

f0 uid for operating servo-motor 94 -95 flows to and from cylinder 95 through a port 98 extending through the walk of sleeve 93' and normally arrangedbetween two spiral grooves 99 and mo which are formed in the peripheryof valve 96. Groove 99 is drained into casing I through at leastone holelllll formed in the inner end of sleeve 93 Groove- 00 communicates with a passage Hi2 formed within vaive 96' and communicatingwith a port l-fl3- which is formed in the head of cylinder 95' around valve 96 and connected by a channel I'M to a supply of liquid so that groove Hill is constantly supplied with motive liquid. For example; channel [04 may be connected: togear pump I l-l8 as shown in Fig. 91

When valve 96 is rotated counterclockwise as viewed from the right end of Fig; 2, groove I00 will move into registry with port 98 and then liquid will* flow from channel I04 through port I03, passage [-02, groove H30 and port 98 into cylinder 95 andcausepiston 94 to move toward the left and: swing lever 90* counterclockwise upon shaft 91'. Lever 90 will move link 84 and pin- 83 toward the left to thereby rotate cam ring counterclockwise in respect to Fig. 2 and to also move connectingrod and piston 86 toward the left, the efiectivearea of piston '94; being enough greater than that of piston 86 to enable piston 94 to movetoward the left when cylinders 8-1 and 95 areboth supplied with liquidat the same pressure.

Piston 94 in moving toward the left will move port 98 with it and tend toclose communication between groove I00 and port 98 as fast as rotation of valve 96 opens communication therebetween. Consequently; cam li'llg- 80 will be rotated through anangular distance exactly proportional to the angular distance through which valve QGisrOtated.

When valve 96 is rotated clockwise as'viewed from the right end of Fig; 2; groove 99 will move into registry with port 98' and then the liquid constantly supplied to cylinder 81 will cause piston 86- tomove connecting rod 85-, pin 83 and link 85 toward the right, pin 83 will rotate cam ring 813 clockwise in respect to Fig. 2, link 84 will swing; lever upon shaft 9i, and roller 92 will move piston 94- toward the right and cause it to eject liquid from cylinder through port 98, groove 99' and hole- NH into casing I. Piston 9A in moving toward the right will move port 93 with it and tend to close communication between groove 9'9 and port 98 as fast as rotation of valve 96 opens communication therebetween. GonSe'quentIy, cam ring 80 willb-e rotated through an angulardistance exactly proportional to the angulardistance through which valve 96 is rotated.

Channels 88 and [04 may be connected to one branch of a supply channel H38 (Fig. 9-) into which gear pump l 1--l-8 discharge liquid drawn from a reservoir [09. The liquid discharged by gear pump [1-48 in excess of requirements is exhausted througha relief valve H0 which enables gear pump. I i-[8 to maintain a constant pressure, such as 85 lbs; per sq. in., in channel H38. The-outlet of relief valve- H0 is connected by a channel II I to the inlet of a relief valve H2 through which liquid in excess of requirements is exhausted into reservoir I09 and which is adapted to open at a pressure lower than the pressure required to open relief valve Hllso that it does not efiect' the pressure in channel I08.

Relief valve M2 also resists the discharge of "1 1 liquid from a valve bore H3 having an automatic suction valve H4 fitted therein. Bore H3 has two annular grooves or ports II 5 and H6 formed in its wall and spaced from its opposite ends, and it communicates at a point intermediate ports II 5 and H6 with channel III and 'with a check valve II! which permits liquid to be drawn into bore II 3 from reservoir I 69 but prevents discharge of liquid from bore H3 into reservoir I09 except through relief valve I I 2.

As previously explained and as shown in Fig. 8, main ports 4| and 4| communicate with a passage 43 having two branches 44 and 45 for connection to an external circuit and to a suction valve respectively, and main ports 4I and 4I communicate with a passage 46 having two branches 41 and 48 for connection to an external circuit and to the uction valve respectively. These passages are represented schematicall in Fig. 9 by channels which bear the same refer ence numerals as the passages in Fig. 8.

As shown in Fig. 9, main ports 4| and 4| b communicate with a channel 43 having a branch 44, which is adapted to be connected to an external circuit, and a branch 45 which is connected to the port H6 of the automatic suction valve and provided with an auxiliary branch 45 which communicates with the right end of bore I I3. Main ports 4| and 4I communicate with a channel 46 having a branch 41, which is adapted to be connected to an external circuit, and a branch 48 which is connected to the port I I5 of the automatic suction valve and provided with an auxiliary branch 48 which communicates with the left end of bore H3.

The arrangement is such that, when the pump discharges liquid into ports 4I and 4I-as previously explained, the-liquid discharged by-the pump will flow through channels 46 and 41 to the external circuit since it cannot flow into reservoir I09 for the reason that at this time valve H4 is blocking port H5. The liquid returned from the external circuit flows through channels 44 and 43 and ports 4| and 4I to the interior of the pump. If the liquid returned from the circuit is in excess of pump requirements, the excess liquid is exhausted through channel 45, bore Hit-and relief valve H2 into reservoir I09. -If--.the liquid returned from the circuit is insufiicient, a part or all of the liquid discharged by gear pump I'|I8 into channel III will flow therefrom through bore H3, channels 45 and 43 and ports 4| and 4| to the interior of the pump. If the liquid returned from the circuit and the liquid discharged by gear pump I'I--I8 into channel III do not together provide sufiicient liquid for pump requirements, the pum will draw liquid from reservoir I69 through check valve I I 7, valve bore I I3, channels 45 and 43 and ports 4| and 4| into the pump.

When the pump is reversed so that it discharges into ports 4| and 4| the liquid-discharged by the pump will tend to flow through channels 43 and 45 and valve bore I I3 into reservoir I69 but check valve II'I prevents flow into reservoir I09 except through relief valve H2 which resists the discharge of liquid-therethrough and thereby causes pump pressure to riseand liquid to flow through branch 45 to the right end of bore I I3 and cause valve H4 to shift-toward the left and block port I I 5 so that the liquid dis- 4 charged by the pump cannot enter bore H3 but must flow into the external circuit.

Liquid returned from the circuit flows to the pum through channels 41 and 46and ports M a 1% an ex ess-is d sc ar d: th u h.

lief valve H2 and any deficiency is made up by gear pump Il--I8 and also if necessary by liquid drawn through check valve I I I. When the pump is again reversed so that it discharges into channel 46, relief valve H2 will cause pressure to rise and liquid to flow through branch 48 to the left end of bore H3 and cause valve H4 to shift toward the right to the position shown and block port H5 so that the pump cannot discharge through relief valve I I2.

When the pump is running idle and when the pressure created by it is less than gear pump pressure, bridges 24 and 24 or bridges 24 and 24 may be moved inward by liquid supplied to recesses 35 and 35 'or recesses 35 and 35 from gear pump I1I8 at the pressure determined by relief valve III] which pressure is high enough to enable the gear pump liquid to exert sufiicient force upon the outer ends of the bridges to move the bridges inward against the outward forces exerted thereon by springs 58 and 59 and by the low pressure acting upon the inner ends of the bridges.

If relief valve IIII should be adjusted to enable gear pump I'II8 to deliver liquid to the recesses at a pressure high enough to effect operation of the bridges when main pump pressure was maximum, excessive power loss and heating of the liquid would result. Therefore, the bridges are operated by liquid at gear pump pressure or main pump pressure whichever is the higher.

Asshown schematically in Fig. 9, gear pump supply channel I08 is connected to a distributing channel'l 2| through a check valve I22 which permits liquid to flow from channel I08 into channel I2I but prevents fiow in the opposite direction. Channel I2I is connected to channel 43 through a-check valve I23 and to channel 46 through a check valve I24 so that the pressure can extend from channel 43 or channel 46 into channel IZI but liquid cannot flow from channel I2I into either channel 43 or 46, and distributing channel I2I is connected to the supply passage 69 (Fig. 5) in each of bridges 24, 24, 24' and 24.

Distributing channel I2I may be an internal passage formed within the pump structure but for the purpose of illustration it has been shown in Fig. 9 as an. external channel and as being connected to the supply passages in bridges 24, 24, 24 and 24 through channels I25, I I25 and I25 respectively. As shown in Figs. 1 and 5 channel I25 has its inner portion arranged radially within cheek plate I II with its inner end in communication with the passage 69 in bridge 24 and its outer portion extending axially through cover plate II and end head 3 so that it passes around gear pum I'|I8. As shown in Fig. 1, channel I25 extends axially through end head 3, cover plate II and cheek plate I0 into communication with the passage 69 in bridge 24 Channels I25*- and I25 are the same as channel I25 and are indicated schematically in Fig. 9 but do not appear in the other figures.

It has previously been explained that in a vane type, hydrodynamic machine the inner ends of the vane slots register successively with a plurality of vane slot ports which are formed in the inner face of one of its cheek plates and that liquid may flow to and from the vane slot ports through channels which communicate therewith and through which pressur may be transmitted for urging the vanes outward against the vane track.

. Since such anarrangement of vaneslot ports is wellv known it" has: not been? completely illustrated in. detail but has been: shownischematically plate It], rotor 6 being indicated by a dot and.

dash circle.

shown in Fig; 9, check plate i i] has formed in its: rear or inner facefour arcuate vane slot ports i3l, I32, it and I34, which are spaced radially inward from: ports ll, 44*, 4t and M respectively, and four short vane sl'ots ports T35 I36, [31 and F38 which are spaced radially inward from bridges 24', 24' 2'4 and 2W respectively. Vane slot port-s I 3! and i 32 also appear in Fig. 7 and vane slot ports I and F3 1 also appear in'Fig. l.

During rotation of the rotor, each vane moves radially outward and draws liquid into its slot from a vane slot port as its outer end travels along the vane track from a sealing bridge to a working bridge, the outer end portion ofthe vane transfers liquid from an intake port toa discharge port as it passes across the working bridge, and the vane moves radially inward and ejects liquid from its slot into a vane slot" port as itsouter end travels along thevanetrack from the working" bridge to the adjacent sealing bridge.

Varies passing across the working bridgethus pump' a principal volume of liquid and the vanes inmoving rauiially pump a secondary volume of liquid which is proportional: totheprincipal vol nine. and equal to a substantial portionthereof.

Forexample; the pumpps-hown i's capab'l'e-of pumpe ing 32;000 cu. in. per minutedue to the passage of its vanes across the working bridges and approximately 390'0 cu. per minute due to the radial movement or its vanes, thus making a total discharge or approximately 351000 011; per minute.

When the machine i's'usedas: a pump, the rotor is rotated at high speed and it is ordinarily only necessary to: hydrostati'cally balance the vanes as the centrifugal force is ordinarily sufii'cient to hold the vanes in contact with the vane track but,. when the: rotor is rotatedl atsl'ow speed and when. the. machine is functioning as a motor and is. started; under a load; the vanes-r must be positively urged against:- the vane track- In order to hold. the outer ends. of the vanes in: contact with. the track. surfaces: on the br dges; the vane slot. ports which are spaced: radiallyrirrward. from the bridges; are supplied; with. liquid first at a low pressure and then at pump pres.- sure, a. pressure higher than pump pressurabeing unnecessary asthe outer end portions of avane have: pump pressure: on one side: thereof and: a low or negative pressure; onthe other side thereof during almost. its. entire journey across. the track surface. on abridge so that'pumppressure acts upon only a portion;- of the outer end area of the vane.

The vane slot ports spaced inward. from the bridges may be connected: to.- each other by a channel formed inithe. pump; structure and that channel. connected. to suitable sources. of pressure but for the purpose oi? illustration vane slot ports I35, I35, t3 and. H8 have: been shown in Fig. 9 as being connected, respectively, tochannels I25, 125 Il -d and Hill by channels Mtg Mill M2 and M3: respectively. Channels M9 and IA 2; also appear in 14 Im order to utilize; the. liquid. pumped: by: the radial= movementzofi'the varies and to provide. pres.- sure: for urging, the. vanes outward against the vane track, the vane slot ports spaced inward f th makepnnts ar connected. to" each other,

to the gearpump. andlto one side of the external circuit and the vane slot ports spaced. inward from discharge: ports are connected to each other", to the gear pump: and to the other side of the external circuit.

As: shown in. Fig; 9:, vane slot ports li-ilr and. IE3 are: connected to each other by a channel M4 which is formed in cheek plate It, they are also connected. through a channel and a check valvel46 to: gear: pump supply channel l'flB and are also connected through a channel l i'l', a check valve" Mili and a resistance valve I49 to channel 43, vane slot ports E32 and 321 are connected; to each other by a channel. E53 which is formed in cheek plate ECG, theyare also connected through a channel. I251? and. acheck valve I52 to gear pump suppty channel M8. and are alsoconnecte'd through a channel i5 3, a: check. valve I54 and: a; resistance. valve r55 to channel it.

Check valves Mill and. 555; permit liquid to flow from: theexternal circuit intothe vane slot ports connected thereto but. they prevent flow from these ports. into the external circuit except through. resistance valves M 9: and- !55. Check valves Mt and: T52 preventliquidfrom flowing from the vane slots connected: thereto into channel H38: but they permit liquid to flow from channel I08 to the inner ends of the outward moving. vaneswhenever, as isusuall y the case, the

liquid delivered: to the inner ends of those vanes from the: external circuit is ihsuiiicient. to keep theirslotsfilled with liquid.

Resistance valve M9 has-two ports N53 and lti formed its casing Hi2" and connected; respectively; to channels 43 and M1. Communication between ports 1-56 and int is controlled by a-valve F63 having a piston F64 arranged upon its inner enct and fitted a bore i 55 formed in casing F52 Port 1 communicates with the inner part of bore: I651 through a duct I56 which extends axially through valve. M33 and. piston use so that whatever pressure is: prevailing in port its. will act upon the: inner or large face ofi'piston !54 and. urge Valve [532 toward; its: seat, valve I63 being urgedz. against. its seat. by a light spring-t Mil" arranged in the. inner part of bore I 65i.

.Port Itl. communicates with the: outer end of bore: I265 througlr a. slottfit whichis formed in the periphery of valve:- lfiS; so that: whatever pressure is. prevailing.- port Mil: will: act upon the outer or small face of piston Hit and tend to move valve Hi3- away from: its seat too-con communication between" ports ltfi and l 51-. The'parts are: so; proportioned. and: the tension of spring H5"! is such-i that the drop pressure across resistance valve M8 is somewhat greater than the pressure createdby gear pump i i-i3. For example, resistance valve MS may be adapted to openresponse tothe pressure in port i=5! becoming. lbs. per; sq; in. greater than the pressure port. N58. Since resistance valve l 55. is identical to: resistance valve its; itsparts have been. indicated by the same reference numerals that. are applied to corresponding: parts of resistance valve Mal and a description thereof is deemed unnecessary...

The arrangement. is such that, whenthe' parts are-in the-positions shown. and rotor. 6 isro- 7 tailed! in. the directions oi the; arrow so: that the pump is discharging through ports M and "4I into channel 46, liquid returned from the circuit will flow through channel 43 to ports M and 4| liquid may flow into vane slot ports I3I and I33 from channel 43 through check valve I48 and channels I41 and I44 and from channel I08 through check valve I46 and channels [45 and I 44 to keep the slots of the outward moving vanes filled with liquid at gear pump pressure so that the outward moving vanes have their inner ends subjected to gear pump pressure which holds the outer ends thereof in engagement with the vane track.

As the vanes pass from a working bridge to a sealing bridge, they will be forced inward by the vane track and the outer ends of the vanes will be subjected to the pressure created by the pump which pressure if unopposed would move the vanes inward out of engagement with the vane track. However, the inward moving vanes will eject liquid from their slots into vane slot ports I32 and I34 from which this liquid can escape, due to check valves I52 and I54, only through resistance valve I55 which prevents the discharge of liquid therethrough until the inward moving vanes have created a pressure which is enough higher than pump ressure to enable theliquid acting upon the small area of piston I64 to exert a force which exceeds the total force exerted upon the large area of piston I64 by the pump pressure and by spring I61. Then resistance valve I55 will open and permit the liquid pumped due to radial movement of the vanes to flow into channel 46 to augment the liquid pumped due to rotary movement of the vanes, and the pres:- sure required to open resistance valve I55 will act upon the inner ends of the inward moving vanes and positively hold the outer ends of those vanes in engagement with the vane track.

When bridges 24 and 24 are moved to their innermost positions and bridges 24 and 24 are moved outward, the pump will function in the above described manner except that the flow to and from the main and vane slot ports will be reversed. That is, the pump will discharge through main ports 4| and 4I into channel 43, main ports M and 4i will be supplied with liquid through channel 46, vane slot ports I32 and I34 will be supplied with liquid through one or both of check valves I52 and I54, the vanes passing across ports M and 4I will be forced inward by the vane track and will eject liquid from their slots into vane slot ports I3I and I33, and escape of liquid from vane slot ports I3I and I33 will be prevented by check valves I46 and I48 except through resistance valve I49 which will cause the inward moving vanes to create suflicient pressure to hold the outer ends of those vanes in engagement with the vane track.

In prior hydrodynamic machines of the sliding vane type, the vane slot ports formed in the inner ,face of a cheek plate were customarily connected to channels which were formed in the opposite face of the cheek plate and closed on their open sides by the flat surface that constituted the bearing for the cheek plate. Thepressure in these channels caused liquidto seep between the outer face of the cheek plate and the supporting fiat surface and form a film therebetween, the pressure in the high pressure channels would extend into the film adjacent those channels, and the pressure in the high pressure channels and in the adjacent film would cause the cheek plate to yield inward toward the rotor. Since there 'is only a running clearance between-theinner face of a check plate and the end of the rotor, a very slight yielding of the cheek plate would cause it to engage the end of the rotor and impose a drag or brake load thereon and thereby not only decrease the eificiency of the machine but also cause excessive wear of the parts with the result that the machine would have excessive slip at low pressures.

In order to overcome the above objectionable characteristics of prior machines, the present invention provides a cheek plate having channels formed in the interior thereof. For example,

channels I40, I4I, I42, I43, I44 and I50 may be formed in the interior of cheek plate I0 as indicated in Fig. 1 in which channels I40 and I42 appear and as indicated in Fig. 7 in which channels I44 and I50 appear. With the vane slot ports connected to a source of pressure liquid through channels formed in the interior of a cheek plate, the pressure in those channels cannot force the cheek plate against the end of the rotor and cause loss of eliiciency and excessive wear. This feature is not claimed herein but is claimed in a divisional application Serial No. 39,866, filed July 21, 1948.

It is sometimes possible to connect ports in the inner face of a cheek plate to a source of pressure liquid through channels which extend axially outward from those ports. If such an axial channel is located so far radially inward from the spacer ring that high pressure in the channel might cause liquid to seep between the outer face of a cheek plate and its supporting surface and force a film therebetween so that pressure could extendinto the film and deflect the cheek plate against the end of; the rotor, deflection of the cheek plate may be prevented by forming a drain passage in the cheek plate or in its supporting surface around the channel and connecting the drain passage to drain as indicated in Fig. 1, in which a drain passage I I0 is formed in cover plate II around channel I25 and connected to drain passage I1.

The hydrodynamic machine disclosed herein may be modified in various ways and adapted to various uses without departing from the scope of the invention which is hereby claimed as follows:

1. In a hydrodynamic machine having high and low pressure ports and a vane track including a plurality of bridges each of which is arranged between a high pressure port and a low pressure port, two bridges constituting a pair and at least one bridge of a pair being adjustable to vary the displacement of said machine, the combination with an adjustable bridge of'hydraulic means for adjusting the same, said hydraulic means including a pressure chamber, a source of constant pressure liquid, means for supplying liquid from'said source to said chamber to energize said hydraulic means, and means for supplying" liquid at a pressure higher than said constant pressure to said chamber in response to the pressure in said high pressure port exceeding said constant pressure.

2. In a' hydrodynamic machine having high and'lowpressur p'orts'and a vane track includinga plurality of bridges each of which is arranged between a high pressure port and a' low pressure port, two bridges constituting a pair and at least one bridge of a pair being adjustable to vary the displacement of said machine, the combination with an adjustable bridge of hydraulic means for adjusting the same, a source of constant pressure liquid, means including a follow-up valve for supplying liquid from said source to said hydraulic means to energize the same, and means for supplying liquid to said valve at the pressure prevailing in said high pressure port in response to said pressure exceeding said constant pressure.

' 3. In a hydrodynamic machine having high and low pressure ports, a rotor, and cheek plates arranged upon opposite ends of said rotor, the combination of a recessed spacer ring arranged around said rotor to hold said cheek plates in spaced relation, an articulated vane track, arranged around said rotor and within said spacer ring and including a plurality of bridges each of which is arranged between a high pressure port and a low pressure port, two bridges constituting a pair and at least one bridge of, a pair being adjustable to vary the displacement of said machine, said adjustable bridge being fitted in a recess in said spacer ring to form therewith a servo-motor, means for supplying liquid to said servo-motor to energize the same including' a valve for controlling the flow of liquid to and from said servo-motor, and means for adjusting said valve to effect operation of said servo-motor and thereby effect adjustment of said bridge.

4. In a hydrodynamic machine having high and low pressure ports, a rotor, and cheek plates arranged upon opposite ends of said rotor, the combination of a recessed spacer ring arranged around said rotor to hold said cheek plates in spaced relation, a vane track arranged around said rotor and within said spacer ring and in-.

cluding a plurality of bridges each of which is arranged between a high pressure port and a low pressure port, two bridges constituting a pair and at least one bridge of a pair being adjustable to vary the displacement of said machine, said adjustable bridge being fitted in a recess in said spacer ring to form therewith a servo-motor, means for supplying liquid at a constant pressure to said servo-motor to energize the same including :a valve for controlling the flow of liquid to and from said servo-motor, means for adjusting said valve to efiect operation of said servo-motor and thereby effect adjustment of said bridge, and means for supplying liquid at a pressure higher than said constant pressure to said valve in response to the pressure in said high pressure port exceeding said constant pressure. 5. In a' hydrodynamic machine having high and low pressure ports, a rotor, and cheek plates arranged-upon opposite ends of said rotozg the combination of a recessed spacer ring arranged around said rotor to hold said check plates in spaced relation, an articulated vane track arranged around said rotor and within said spacer ring and including a plurality of bridges each of which is arranged between a high pressure port and a low pressure port, two bridges constituting a pair and at least one bridge of a pair be-' ing adjustable to vary the displacement of said machine, said adjustable bridge being fitted in a recess in said spaced ring to function as a piston and having formed therein .a Valve bore and passages leading from said bore for the flow of liquid through said bore to and from said recess, means for supplying liquid to said bore, a valve fitted in said bore for controlling the flow of liquid to and from said recess, and means for adjusting said valve.

6. In a hydrodynamic machine having high and lowpressure ports, a rotor, and cheek plates 18 arranged upon opposite ends of said rotor, the combination of a recessed spacer ring arranged around said rotor to hold said cheek plates in spaced relation, an articulated vane track arranged around said rotor and within said spacer ring and including a plurality of bridges each of which is arranged between a high pressure port and a low pressure port, two bridges constituting a pair and at least one bridge of a pair being adjustable to vary the displacement of said machine, said adjustable bridge being fitted in a recess in said spacer ring to function as a piston and having formed therein a valve bore and passages leading .from said bore for the flow of liquid through said bore to and from said recess, means for supplying liquid to said bore, a valve fitted in said bore for controlling the flow of liquid to and from said recess, means for adjusting said valve, and means yieldingly retaining said valve in engagement with said valve adjusting means to enable said valve and bore to function as a follow-up valve and thereby prevent said bridge from wandering from the position determined by said valve adjusting means.

7. In a hydrodynamic machine having a rotor, the combination of a vane track arranged around said rotor and including a plurality of bridges all of which are movable toward and from said rotor to vary the displacement of said machine and to reverse said machine if it is a motor or to reverse the flow if themachine is a pump, two adjacent bridges constituting a pair and one bridge of said pair being closer to the rotor than the other bridge when the machine is performing useful work, means for moving each bridge toward and from said rotor, and means for operating the moving means for either bridge of a pair without effecting operation of the moving means for the other bridge of that pair so that either bridge of a pair may be caused to move toward or from said rotor while the other bridge remains stationary.

8. In a hydrodynamic machine having a rotor, the combination of a vane track arranged around said rotor and including a plurality of bridges which are movable toward and from said rotor to vary the displacement of said machine and to reverse said machine if it is a motor or to reverse the flow if the machine is a pump, two bridges constituting a pair and one bridge of each pair being closer to the rotor than the other bridge when the machine is performing useful work, the bridges closer to the rotor constituting one set and the other bridges constituting a second set, means for moving each bridge toward and from said rotor, and means for operating all of said moving means and adapted to operate the moving means for either set of bridges simultaneously without effecting operation of the moving means for the other set of bridges.

9. In a hydrodynamic machine having a rotor, the combination of a vane track arranged around said rotor and including a plurality of bridges which are movable toward and from said rotor to vary the displacement of said machine and to reverse said machine if it is a motor or to reverse the flow if the machine is a pump, two bridges constituting a pair and one bridge of each pair being closer to the rotor than the other bridge when the machine is performing useful work, the bridges closer to the rotor constituting one set and the other bridges constituting a second set, a servo-motor for effecting movement of each bridge-toward and from said rotor, means for supplyingiliquid to each servo-motor to energize 19 the same including .a valve for controlling the flow-oi liquid toand fronr-each servo-motor, and means for operating said valves and adapted to operate the valvesof either set of bridges simultaneously without effecting operation of the valves of the other set of bridges.

10. In a hydrodynamic machine having a rotor and two cheek plates arranged uponopposite ends f said rotor, the combination of a recessed spacer ring arranged around said rotor to hold said check plates in spaced relation, a vane track arranged around said rotor and within said spacer ring and including a plurality of bridges each of which is fitted in a recess in said spacer ring and forms therewith a servo-motor, two bridges constituting a pair and one bridge of each pair being closer to the rotor than the other bridge when the machine is performing useful work, the bridges closer to the rotor constituting one set and the other bridges constituting a second set, means for supplying liquid to each servo-motor to energize the same including a valve for controlling the fiow of liquid to and from each servomotor, and means for operating said valves and adapted to operate the valves of either set of bridges simultaneously without efiecting operation of the valves of the other set of bridges.

11. In a hydrodynamic machine having a rotor, the combination of a vane track arranged around said rotor and including a plurality of bridges which are movable toward and from said rotor to vary the displacement of said machine and to reverse said machine if it is a motor or to reverse the flow if the machine is a pump, means for moving each bridge toward and from said rotor, a cam ring arranged around said bridges concentric with said rotor, individual cam tracks one for each bridge arranged upon said cam ring and adapted to efiect operation of said moving means to cause said bridges to move-toward and from their innermost positions during angular adjustment of said cam ring, cam tracks arranged upon and concentric with said ring joining said individual tracks and adapted to hold said moving means in such positions that the bridges controlled thereby are held in their innermost positions, said cam tracks being so located-that said individual tracks control alternate moving means only and said concentric tracks control all of said moving means in one position of said ring and control alternate moving means in all other positions of said ring, and means for adjusting said ring to various angularpositions.

' 12. In a hydrodynamic machine having a rotor, the combination of a vane track arranged around said rotor and including a plurality of bridges which .are movable toward and from said rotor to vary the displacement of said machine and to reverse said machine if it is a'motor'or to reverse the fiow if the machine is 'a pump, means for moving each bridge toward and from said rotor, a cam ring arranged around said bridges concentric with said rotor, individual cam tracks one foreach bridge arranged'upon said cam ring and adapted to effect operation of said moving means to cause said bridges to move toward and from their innermost positions during angular adjustment of said cam ring, cam tracks arranged upon and concentric with said ring joining said individual tracks'and adapted to hold said moving means in such positions that the bridges controlled thereby are held in their innermost positions, said cam tracks being-so located that said individual tracks control alternate moving means only :and said concentric tracks control all of said moving means in one :position of said ring and control alternate moving means in all other positions of said ring, hydraulic means for adjusting said ring to various angular positions, and'means for supplying liquid to said hydraulic means including a follow-up-valve to control said hydraulic means and enable it to move said ring to and hold it in an adjusted position.

13. In a hydrodynamic machine having a rotor, the combination of a vane track arranged around said rotor and including a plurality of bridges which are movable toward and from said rotor to vary the displacement of saidmachine and to reverse said machine if it is a motor or toreverse the flow if the machine is a pump, a servo-motor for effecting movement of each bridge toward and from saidrctor, means for supplying liquid to each servo-motor to energize the same including avalve'for controlling the flow of liquid to and from each servo-motor, a cam ring arranged around said bridges concentric with said rotor, individual cam tracks one for each valve arranged upon said cam ring and adapted to effect operation of said valves to cause said servomotors to move said bridges toward and from their innermost positions during angular adjust: ment of said cam ring, cam tracks arranged upon and concentric with said ring joining said individual tracks and adapted to hold said valves in such positions that the servo-motors controlled thereby hold said bridges in their innermost positions, said cam tracks being so located that said individual tracks control alternate valves only and said concentric tracks control all of said valves in one position of said ring and control alternate valves in all other positions of said ring, and means for adjusting said ring to various angular positions.

'14. In a hydrodynamic machine having a rotor, the combination of a vane track arranged around said rotor and including a pluralit of bridges which are movable toward and from said rotor to vary the displacement of said machine and to reverse said machine if it is a motor or to reverse the flow if the machine is a pump, a servo-motor for effecting movement of each bridge toward and from said rotor, means for supplying liquid to each servo-motor to energize the same including a valve for controlling the flow of liquid to and from each servo-motor, a cam ring arranged around said bridges concentric with said rotor, individual cam tracks one for each valve arranged upon said cam ring and adapted to effect operation of said valves to cause said servomotors to move said bridges toward and from their innermost positions during angular adjustment of said cam ring, cam tracks arranged upon and concentric with said ring joining said individual tracks and adapted to hold said valves in such positions that the servo-motors controlled thereby hold said bridges in their innermost positions, said cam tracks being 50 located that said individual tracks control alternate valves only and said concentric tracks control all of said valves in one position of said ring and control alternate valves in all other positions of said ring, hydraulic means for adjusting said ring to various angular positions, and means for supplying liquid to said hydraulic means including a follow-up valve to control said hydraulic means and enable it to move said ring to and hold it in an adjusted position.

15. In a hydrodynamic machine having'a rotor, a vane track arranged around said rotor and including a plurality of bridges at least one of which is movable toward and from said rotor to vary the displacement of said machine, the combination with a movable bridge of a structure enclosing said rotor and provided with a recess to receive said movable bridge and form therewith a hydraulic servo-motor for effecting movement of said movable bridge toward and from said rotor, means for supplying liquid to said servo-motor to energize the same, and a positive stop for limiting the movement of said bridge toward said rotor.

16. In a hydrodynamic machine having high and low pressure ports, a rotor, and cheek plates arranged upon opposite ends of said rotor, the combination of a recessed spacer ring arranged around said rotor to hold said cheek plates in spaced relation, a vane track arranged aroundsaid rotor and within said spaced ring and including a plurality of bridges each of which is arranged between a high pressure port and a low pressure port, two bridges constituting a pair and at least one bridge of a pair being adjustable to vary the displacement of said machine, said adjustable bridge being fitted in a recess in said spacer ring to function as a piston and having formed therein a valve bore and passages leading from said bore for the flow of liquid through said bore to and from said recess, a source of constant pressure liquid, means for supplying liquid from said source to said bore, means for supplying liquid at a pressure higher than said constant pressure to said bore in response to the pressure in said high pressure port exceeding said constant pressure, a valve fitted in said bore for controlling the flow of liquid toand from said recess, and means for adjusting said valve.

17. In a vane type hydrodynamic machine having high pressure and low pressure ports, a rotor provided with radial vane slots and a vane slidably fitted in each of said slots, the combination of an endless vane track extending around said rotor and including a plurality of sealing bridges and a plurality of working bridges each of which is arranged between a high pressure port and a low pressure port and a plurality of extensible vane track sections each of which is arranged between adjacent bridges, means for moving said working bridges toward and from said rotor to vary the displacement of said machine, each of said track sections having a concave track surface upon its inner face and each of said bridges having upon the inner face thereof a track surface which is concave intermediate its ends for a distance at least as great as the distance between the outer ends of two adjacent vanes, and posts fixed to each of said track sections at opposite ends thereof and pivotally connected to the adjacent bridges at points Spaced substantial distances radially outward from said track surfaces.

18. In a vane type hydrodynamic machine having high pressure and low pressure ports, a rotor 22 provided with radial vane slots and a vane slidably fitted in each of said slots, the combination of an endless vane rack extending around said rotor and including a plurality of seaiing bridges and a plurality of working bridges each of which is arranged between a high pressure port and a low pressure port and a plurality of extensible vane track sections each of which is arranged between adjacent bridges, means for moving said working bridges toward from said rotor to vary the displacement of said machine, each of said track sections having a concave track surface upon its inner face and each of said bridges having upon the inner face thereof a track surface which is concave intermediate its ends for a distance at least as great as the distance between the outer ends of two adjacent vanes, recesses formed in said bridges and extending a substantial distance from the inner faces of said bridges, posts fixed to each of said track sections at opposite ends thereof and extending substantial distances into said recesses, and pins carried by said bridges and extending through the outer ends of said posts to pivotally connect said track sections to said bridges.

WALTER FERRIS.

REFERENCES orrsn The following references are of record in the of this patent:

UNITED STATES PATENTS Number Name Date 1,693,540 Balsiger Nov. 27, 1928 2,016,315 Calzoni Oct. 8, 1935 2,080,810 Douglas May 13, 1937 2,142,500 Douglas June 3, 1939 2,179,071 Wiedmann Nov. 7, 1939 2,198,935 Ferris Apr. 23, 1940 2,214,552 Ferris Sept. 10, 1940 2,222,144 Ferris Nov. 19, 1940 2,238,061 Kendrick Apr. 15, 1941 2,238,062 Kendrick Apr. 15, 1941 2,238,063 Kendrick Apr. 15, 1941 2,255,785 Kendrick Sept. 16, 1941 2,256,459 Kendrick Sept. 16, 1941 2,280,190 Ernst Apr. 21, 1942 2,313,246 Kendrick et al Mar. 9, 1943 2,335,284 Kendrick Nov, 30, 1943 2,385,069 Ferris Sept. 18, 1945 2,389,829 Tyler Nov. 27, 1945 FOREIGN PATENTS Number Country Date 101,021 Switzerland Sept. 1, 1923 226,082 Great Britain Dec. 18, 1924 313,642 Italy June 2, 1934 370,358 Italy Apr. 14, 1939 373,230 Italy 1939 386,018 Germany Dec. 1, 1923 388,695 Germany Mar. 22, 1924 812,024 France Jan. 27, 1937 

